This invention is concerned with a clamp for use in sealing the gap between a pair of confronting pipe flanges integral with the ends of two pipes which have been bolted together to form part of a pipe line. Such flanges are usually bolted together using an intervening gasket to prevent leakage. When the flanges are bolted together, the gasket, in the form of an annular seal, is clamped between the flanges, normally radially inwardly of the bolts. If the gasket develops a fault, because it has been subjected to the prolonged action of corrosive fluid, for example, then a leak may occur through it and release fluid between the flanges. If the fluid supply cannot conveniently be interrupted, then steps may have to be taken to stop the leak whilst the pipe still contains fluid and until a permanent repair can be effected.
One conventional procedure for closing such leaks is to hammer a malleable wire into the annular gap between the confronting outer edges of the flanges; these edges are then peened over to hold the wire in place. Holes are then drilled or tapped through at least one of the flanges into the space between the wire and the existing, but leaking gasket and a sealant material is then injected through these holes to fill the space and at the same time stop the leak. This procedure of caulking with wire followed by drilling holes and injecting a sealant material is a very specialised technique which requires significant skill and training if it is to be carried out safety and effectively. In particular, great care has to be taken when drilling the holes if the pipe is carrying a potentially explosive fluid. Typically the invention is concerned with leaks in the flanged joints of high pressure lines for industrial processes involving, for example, water, steam, acid, various gases, hydrocarbons, compressed air or oil. The kind of hazard which may be involved is self-evident.